The invention relates to a motor vehicle door lock with a locking mechanism, essentially comprising a catch and pawl, with the pawl containing a contact surface against which the catch rests when the locking mechanism is closed.
In a motor vehicle door lock of the above design, as disclosed in DE 10 2009 029 031 A1, the pawl has a closing moment in the main latching position of the locking mechanism, changing to an opening moment during closing of the locking mechanism. This aims to provide a relatively quiet opening of the known motor vehicle door lock. Such a motor vehicle door lock presents the fundamental problem that the catch and/or the pawl are released more or less abruptly and move apart. At the same time, the pawl or the catch often move against the associated stops.
Such abrupt opening movements are caused by or are a result of relatively great forces acting on the locking mechanism of the motor vehicle door lock or the locking bolt retained in the closed state of the locking mechanism. In most cases these are caused by one or several rubber door seals with the aid of which a respective motor vehicle door is sealed from a car body. When closing the motor vehicle door, the respective rubber door seal is compressed and produces respective resetting forces or a counter pressure which is or are then released when the locking mechanism is opened.
At this point forces or torques often exceeding 500 N m appear at the locking mechanism, resulting in a “plopping noise” typically associated with the opening operation. Most operators find these noises annoying, in particular, as the respective motor vehicle door often amplifies noises at this point as it causes an amplifying resonance or as the noises are transferred as structure-borne noises to the motor vehicle body. This applies in particular for tailgates.
The state of the art disclosed in the aforementioned DE 10 2009 029 031 A1 uses at this point preferably a flat surface in the contact area between the pawl and a contour of the catch, which together with a contact area of the pawl serving to latch the catch, forms an angle of between 120° to 150°. This has generally proven to be successful. The components of the locking mechanism, i.e. essentially the catch and the pawl are, however, punched steel parts that are (can) only be manufactured with a certain accuracy. The same also applies to a normally solid lock case, also made of steel, containing the rotary axes for the locking mechanism parts mounted therein. In other words, the geometric conditions described in DE 10 2009 029 031 A1 can not always be implemented without problems in practical application. This also applies to the further prior art disclosed in DE 23 26 808 A. The invention aims to remedy this.